Gear-cutting machine.



M. MAAG.

GEAR CUTTING MACHINE.

APPUCATIQN FILED AUGESO, 191s.

J?@@m Mme@ May 21,1918.

IsTIE nro.

MXIZMMG, OF ZURICH, SWITZERLAND.

GEAR-GUTTING 'MCHHIE.

I Speeication oi Letters Patent.

.Application led Aug-ust 36, 1916. Serial No. 117,705.

ments in Gear-Cutting Machines; and l do hereby declare the fdllowing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the ac companying drawing, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to improvements in gear-cutting machines having a blank-carrier, which besides receiving during the cutting operation a successive rolling movement, consisting of ayrevolving movement and a longitudinal travel, carries out during the time outside the cutting operations, z'. e.,

' between succeeding cutting operations some additional movements during which a mul tiple-tooth cutter of rack form has to be prevented from coming in contact with the teeth to be cnt.y 1n order to bring the cutting tool during said additional movements out of contact with the blank, the machine forming the subject-matter of my present invention has means adapted to swing said tool backward while the tool carrier is still moved. These means are then adapted to keep at the same time the tool out of reach of the blank until a new cutting operation is restarted.

rlhc hereinafter described construction is particularly adapted to be applied to gearcutting machines working according` .to the rolling principle and having a central drum controlling the different movements of the machine and a reciprocating ram provided with a hinged tool holder. As this tool Iholder can be swung backward only during lib the upward movementof the ram, or while the ram is in its uppermost or lowest posi4 tion .l provide a construction in which the movement of the hinged tool holder, during the time outside the cutting operations, is initiated by said central control druni,while the releasing of this movement is effected by a shaft which may be driven either by the feed-shaft of the machine or a cam-disk shaftv actuating the ram carrying the tool holder.

This invention will now be more particuu larlv described with reference to the acconc-1 panying drawing, which illustrates apreferred form of the invention.

In this drawing:

Figure 1 is a side view partly in section of the gear-cutting machine,

Fig. 2 isa section on the line A-B of Fig. 1,

Fig. 3 is a section on the line C-D of Fig. 1; i y

Figs. 4 and 5 are vertical sections through the ram carrying the hinged tool holder,

Fig. 6 is a rear view of a part of the ma-` chine and Figs. 7 and 8 are sections on the line E-F l of Fig. 6 showing the parts inl diierent working positions.

ln carrying this invention into edect as shown in the drawing I provide a tool ram 2 adapted to reciprocate in the guidance 1 in the direction of the double arrow 43 (Fia. 1). A cam-disk 4 and a slide 3 transmit the movement of a constantly revolving shaft 5 to said ram 2. Shaft 5 is driven by the main driving shaft 5a. To the ram 2 is hinged the clapper-box or ltool holder plate 6 carrying the cutting tool 7 and adapted to oscillate in the direction of double arrow 40 (Fi 5) about bolt 8. A spring 44l (Fig. 1 has the :tendency to swing said clapper-box 6 in a forward, that is, clockwise direction, while levers 9 and 10 (Figs. h3, 4, 5) may eiiect a backward oscillation of this clapper-box or plate 6. The lever 10 is fixed to a vertical shaft 11 (Figs. Sand l), which carries a toothedwheel segment l2 (Figs. 2, 3) meshing with a toothed-wheel segment 13 fixed to a ver-y tical shaft 14 (Figs. 1 and 2.). To the lower lend of this shaft 14 is fixed a lever 15 resting on the circumference of the cam-disk 4. The already mentioned spring 44 presses this lever 15 against cam 16, which extends ratentea nay ai, raie.

over half the circumference of said disk 4,

so that lever 15 causes, upon each revolution of the cam-disk shaft 5 during the cut -ting operation', an oscillation of the plate lDuring each backward oscillation of the plate 6 brought about by cam 16 while the ram is moved upward, the tool holder is diameter' or' the blank in order to bring it.

out of contact with said blank.

To lever is also fixed a cam 17 acted upon by a shaft 18. The outer end 21 Figs. 1, '7 and 8) of this shaft 18 has the form of a toothed rack which engages with a toothed-wheel segment 19. denotes a lever rigidly connected to this segment 19. A rod 22 connects lever 20 to a lever 3. This lever 23 is formed integral with an arm 26 and it, is loose on shaft 24 to which is fixed a disk 25. The latter is provided on its circumference with a cam 27. Shaft 24 is oscillated during the cutting operation by an arm 4G operatively connected to the camdislg shaft 5 by means of toothed wheels'47, 48 and a cam-disk 49. r1`his arm 46 is moved on each revolution of the disk 49'tl1rough an angle o'. (Fig. 7). Cam 27 referred to is adapted to move a lever 2S acted upon by a draw-spring 28 connected at one end to a part formed integral with this cam and at the other end to lever 23. 31 is also adapted to act upon said lever 28. 29 denotes a movable lever, which is adapted to keep arm in its uppermost position. Said lever 2i) is rigidly connected to a segment '50 and it is acted upon by a spring 30 Aconnected at one end to the 'frame of the machine. rl"his segment 30 may be lifted by a ring 5.32 fixed to the rod 31, the lower end of which carries a roll. 51 resting on the central drinn having a cam 34. rlfhe drum i525 is moved in the direction of arrow by a rod 3ft fixed to a block adaptedl to move in the arm ylo and a disk segment 37 carrying a pawl 3S, which engages with a ratchet wheel 32) fixed to a shaft' 39. ad

p gearing L't1 transn'iits the movement of this shaft. 39 to a shat't t2 (Fig. 8) to which is :fixed said drinn 33.

The l'lereinl'ie't'ore described mechanism for effecting anfoscillation ot'y the hinged tool holder between succeeding cuttingsr operations works as follows:

As already mentioned, the backward swinging of the tool holder t; is initiated by the central drinn 33. The cam 34 ot the latter is arranged in such a manner, that its end is moved past roll 51 carried by rod 81 shortly before the cutting operation is completed. The rod 31 is then moved downward owing to the tendencyl of the spring 28a connected to the, cam 27 as well as to the lever 23, to pull said cam 27 downward. Ring 32 Xed to shaft 31 is then also moved d wnward, so that the lever 29 acted upon by spring 30 and the segment 30 rigidly A vertical rod.

connected to said lever 29 are oscillatcd to a smallamount in a counter-clockwisc direction. Owing to said downward movement of the shaft 31 the nose 5() ol' lever 2S is now able to engage disk Upon the succeeding rotation of this disk 25 in a counter clockwise direction corresponding to an upward movement of the ram, levers 2S and 23 are moved toward the left while rod 22 is moved downward, so that the toothed segment 19 effects a forward movement of shaft 18 (Fig. 8). Thus, lever 15 is also moved in a forward direction and the shafts 14 and 11 are moved in such a manner, that the hinged tool holder (5 is swung backward and brought wholly out of reach ot the teeth of the blank (Fig.

In order to keep now the tool plate t3 in the inclined position shown. in Fig. 5 until the next cutting operation is restarted it is necessary, that the spring 45 be prevented from moving therod 18 in a backward direction until such a new cutting operation is restarted. This is effected by lever 2f), which keeps the lever 2G in its uppermost position (Fig. 8).`

The moving back of the hinged tool holder G into its original position is again initiated by the central drum 33. Shortly before the cutting operationis restarted, the cam S51 of the revolving drum is moved beneath roll 51 carried by the rod 31, so that the latter is lifted. The. ring 32 of this rod ill moves thereby the segment 30 in a clockwise direction, so that also lever 29 is moved toward the right. The spring t5 is now able to move rod 18 toward the right, while lever 23 and arm 26 are moved from the position shown in Fig. S into that shown in Fig. 7. rlhe lever 28 comes thereby again in contact with the rod 31 which then causes the nose 50 to disengage the cam 27. At the same time the spring 44 moves the hinged tool holder back into the original posit ion, that is the position shown in Fig. 4.

lVhat l claim is:

1. In a gear-cutting machine, the combination with` a constantly moved ram, of a tool holder hinged to Said ram and means adapted to swing said holder backward be tween succeeding cuttinr operations each lasting several tool stro (es and keep the holder in this position until a cutting operation is restarted, substantially as described.

2. In a gear cutting machine, means to reciprocate the cutting tool, means to impart a backward movement to the tool during each stroke of the latter in one direction,

.and means to alter the extent of backward movement of the tool at a prcdeternlined number of strokes of the latter', whereby the tool is moved ont of cuttingposition.

3. ,ln a gear cutting machine, means to reciprocate the'cuttinglool, means to impart a backward movement to the tool during 

